Method and apparatus for antenna selection

ABSTRACT

A system that incorporates teachings of the subject disclosure may include, for example, an antenna system coupled with the transceiver that includes a first antenna and a second antenna where one of the first or second antennas is operating as a primary antenna and the other of the first or second antennas is operating as a diversity antenna. The system can include an RF switch connected with the antenna system, where the RF switch has a first position in which the first antenna is the primary antenna and the second antenna is the diversity antenna, and wherein the RF switch has a second position in which the second antenna is the primary antenna and the first antenna is the diversity antenna. The system can include a controller coupled with the matching network and with the RF switch, where the controller receives first reflection measurements associated with the antenna system, and where the controller adjusts the RF switch to select between the first and second positions according to the first reflection measurements.

FIELD OF THE DISCLOSURE

The subject disclosure relates to communication devices and, inparticular, selection of an antenna in an antenna system.

BACKGROUND

Wireless communication devices can operate over a wide range offrequencies such as from 700 to 2700 MHz. Antenna design is made morechallenging by handset requirements that include long battery life, morefrequency bands, larger display screens with reduced borders, andthinner form factors.

Communication devices such as cellular telephones, tablets, and laptopscan support multi-cellular access technologies, peer-to-peer accesstechnologies, personal area network access technologies, and locationreceiver access technologies, which can operate concurrently.Communication devices have also integrated a variety of consumerfeatures such as MP3 players, color displays, gaming applications,cameras, and other features.

Communication devices can be required to communicate at a variety offrequencies, and in some instances are subjected to a variety ofphysical and functional use conditions. For instance, when handling thecommunication device, a user may detune the antenna and/or affect itsradiation efficiency by the users grip, body, or other materials aroundthe communication device.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIGS. 1 and 2 depict illustrative embodiments of communication devicesthat provide antenna selection to improve radiation efficiency;

FIGS. 3A-3F depict communication devices that provide antenna selectionto improve radiation efficiency and depict graphical representations oftuning grids utilized for antenna selection;

FIGS. 4 and 5 depict illustrative embodiments of methods of antennaselection to improve radiation efficiency;

FIGS. 6-12 depict a communication device that provides antenna selectionto improve radiation efficiency, graphical representations of tuninggrids and efficiency data utilized for antenna selection;

FIG. 13 depicts an illustrative embodiment of a method of antennaselection to improve radiation efficiency;

FIGS. 14-15 depict graphical representations of tuning data utilized forantenna selection in the method of FIG. 13;

FIG. 16 depicts a communication device that provides antenna selectionto improve radiation efficiency;

FIG. 17 depicts an illustrative embodiment of a method of antennaselection to improve radiation efficiency;

FIG. 18 depicts an illustrative embodiment of a portion of a transceiverof the communication device of FIG. 1;

FIGS. 19-22 depict illustrative embodiments of a tunable matchingnetwork of the transceiver of FIG. 8;

FIG. 23 depicts an illustrative embodiment of a look-up table utilizedby the communication device of FIG. 1 for controlling tunable reactiveelements and antenna selection utilized by the communication device;

FIGS. 24-27 depict illustrative physical and operational use cases of acommunication device; and

FIG. 28 depicts an illustrative diagrammatic representation of a machinein the form of a computer system within which a set of instructions,when executed, may cause the machine to perform any one or more of themethodologies disclosed herein.

DETAILED DESCRIPTION

The subject disclosure describes, among other things, illustrativeembodiments of devices that selectively switch antennas operating asprimary and diversity antennas. The antenna selection can be based onvarious factors including measuring operating parameters (e.g.,reflection measurements). In one or more embodiments, the reflectionmeasurements can be used for determining a use case of the communicationdevice and determining a preferred or desired antenna to operate as theprimary antenna according to the use case. The use case can be apositioning of the communication device with respect to the user such asBeside Head and Hand Right (BHHR) or Beside Head and Hand Left (BHHL).The use case can also include a physical state of the communicationdevice, such as open flip or closed flip for a flip phone. The use casecan also include a functional state of the communication device, such asspeaker phone or Bluetooth operation.

In one or more embodiments, selective antenna switching can be utilizedin conjunction with impedance tuning for one or both of the primary anddiversity antenna. The particular number of antennas utilized can bejust two or can be more than two antennas. In one or more embodiments,the same measured parameter(s) can be used for both the selectiveantenna switching and the impedance tuning, such as reflectionmeasurements. The impedance tuning can be a closed loop feedback processand/or an open loop feedback process.

In one embodiment, a sense integrated circuit (IC) can perform orotherwise obtain reflection measurements that are used as feedback forclosed loop antenna tuning. A Double Pole Double Throw switch (DPDT)switch can be utilized for antenna selection, so that the transmittercan be routed to the antenna that has the most favorable loadingconditions for radiation. The reflection measurements from the sense ICcan be used to determine the loading conditions of each antenna and canbe used as the selection criteria for the antenna selection.

In one embodiment, transmission Gamma measurements can be utilized forantenna selection according to a tuning grid. A grid location determinedby a closed-loop tuning algorithm can be used as an input for antennaselection. For example, each grid location in a lookup table can have anentry for efficiency. The grid location can be determined by coarsetune. In one embodiment, the grid location can be further refined usingfine tune. In one embodiment, a metric can be a distance from the gridlocation to freespace antenna S11. In another embodiment, instead ofusing the algorithm-derived grid location, measurements (e.g., from thesense IC) can be directly utilized.

In one embodiment, a selection criteria can be based solely onmeasurements with the antenna currently connected to the transmitter,rather than requiring measurements for both antennas. In anotherembodiment, the antenna switching is subject to control by the modemsuch as a controller indicating to the modem (e.g., according toreflection measurements) which antenna is preferred for transmittingwhile the modem indicates to the control which antenna is transmitting.In one example, the reflection measurements that are utilized todetermine whether or not to switch antennas can be limited to theantenna that is currently transmitting. In one embodiment, themonitoring of the reflection measurements and assessment as to thepreferred antenna can continue to be executed while the controller iswaiting for permission from the modem to switch antennas.

In one or more embodiments, the antenna selection systems and processesdescribed herein can be utilized with or without impedance tuning. Whereimpedance tuning is utilized, it can be based on the same operationalparameter(s) as is used in the antenna selection process or can be basedon different operational parameter(s). The impedance tuning can be forone, some or all of the antennas being utilized by the communicationdevice. As an example, different tunable reactive elements can beutilized for impedance tuning of different antennas or the same tunablereactive element can be used for impedance tuning of some or all of theantennas.

In one or more embodiments, closed loop tuning on both antennas can beperformed by toggling an antenna selection switch to perform reflectionmeasurements for tuning algorithm. In these examples, the modem permitsfrequent antenna switching.

In one embodiment utilizing voltage variable tuning and antennaselection, the communication device can efficiently operate over a widefrequency range such as of 700 to 960 (LB), 1700 to 2200 MHz (MB) and2300-2700 MHz (HB). The exemplary embodiments can improve antennaefficiency and radiation efficiency while also enabling selection of themore efficient antenna for transmission. Antenna efficiency isessentially the ratio (e.g., in % or dB) of total power radiating out ofthe antenna divided by total power injected into the antenna. Radiationefficiency is the ratio of “calculated total power radiated out of theantenna if no power was lost due to mismatch”, divided by total powerinjected into the antenna. The latter, radiation efficiency, can be abetter measure of the antenna's ability to radiate, and a better measureof how much power is lost as dissipative energy, either in the ohmiclosses in the antenna/phone device, or if in use case, into the user.

In one or more embodiments, the primary and diversity antennas caninclude parallel coupled radiating elements for LB and for MB and HBcommunications. In another embodiment, the antennas can be set on or inproximity to the bottom (or the top) of the wireless devices (e.g., amobile phone). In one or more embodiments, single feed antennas can beutilized. In one or more embodiments, high antenna efficiency and highradiation efficiency for tunable matching applications can be provided.In one or more embodiments, a small dimension in the y direction can beutilized, which is suitable for a small ground clearance device whichenables larger screens and/or larger batteries without making the deviceoverall dimensions larger.

In one or more embodiments, low ground clearance can be utilized. In oneor more embodiments, good antenna performance can be provided, such asin BHHR for primary and in BHHL for diversity. In one or moreembodiments, low antenna pattern correlation coefficients can beprovided.

One or more of the exemplary embodiments can be utilized inmulti-antenna and/or multi-port antenna systems used to address CarrierAggregation (CA) requirements for handsets, such as LB antennas thatmust cover 700-960 MHz under all use-cases. Other embodiments aredescribed by the subject disclosure.

One embodiment of the subject disclosure includes a mobile communicationdevice having a transceiver, an antenna system, an RF switch, a matchingnetwork, and a controller. The antenna system is coupled with thetransceiver, where the antenna system includes a first antenna and asecond antenna, and where one of the first or second antennas isoperating as a primary antenna and the other of the first or secondantennas is operating as a diversity antenna. The RF switch is connectedwith the antenna system, where the RF switch has a first position inwhich the first antenna is the primary antenna and the second antenna isthe diversity antenna, and where the RF switch has a second position inwhich the second antenna is the primary antenna and the first antenna isthe diversity antenna. The matching network is coupled with thetransceiver and the antenna system, wherein the matching networkcomprises a tunable reactive element. The controller is coupled with thematching network and with the RF switch, where the controller receivesfirst reflection measurements associated with the antenna system, wherethe controller adjusts the tunable reactive element according to thefirst reflection measurements to provide impedance tuning, and where thecontroller adjusts the RF switch to select between the first and secondpositions according to the first reflection measurements.

One embodiment of the subject disclosure is a method that includesobtaining, by a controller of a communication device, first reflectionmeasurements for a first antenna of the communication device operatingas a primary antenna when an RF switch of the communication device is ina first position. The method includes adjusting, by the controller, atunable reactive element of a matching network according to the firstreflection measurements to perform impedance tuning. The method includesanalyzing, by the controller, the first reflection measurements todetermine a desired antenna for transmission. The method includesswitching, by the controller, the RF switch to a second positionresponsive to a determination that a second antenna of the communicationdevice is the desired antenna for transmission, where the switching tothe second position causes the second antenna to operate as the primaryantenna. The method includes obtaining, by the controller, secondreflection measurements for the second antenna operating as the primaryantenna when the RF switch is in the second position. The methodincludes adjusting, by the controller, the tunable reactive elementaccording to the second reflection measurements to perform the impedancetuning. The method includes analyzing, by the controller, the secondreflection measurements to determine the desired antenna fortransmission. The method includes switching, by the controller, the RFswitch to the first position responsive to a determination that thefirst antenna is the desired antenna for transmission.

One embodiment of the subject disclosure is a communication device thatincludes a modem, a transceiver, an antenna system, an RF switch and acontroller. The antenna system is coupled with the transceiver, wherethe antenna system includes a first antenna and a second antenna, whereone of the first or second antennas is operating as a primary antennaand the other of the first or second antennas is operating as adiversity antenna. The RF switch is connected with the antenna system,where the RF switch has a first position in which the first antenna isthe primary antenna and the second antenna is the diversity antenna, andwhere the RF switch has a second position in which the second antenna isthe primary antenna and the first antenna is the diversity antenna. Thecontroller is coupled with the RF switch, where the controller receivesfirst reflection measurements associated with the antenna system, andwhere the controller adjusts the RF switch to select between the firstand second positions according to the first reflection measurements andduring a time period in which the modem enables an antenna switch.

FIG. 1 depicts an illustrative embodiment of a communication device 100.Communication device 100 enables selection antenna selection in amulti-antenna device to improve radiation efficiency. Device 100 canmeasure the complex input reflection coefficient that is used asfeedback for an impedance tuning algorithm. In one embodiment, thecomplex input reflection coefficient can be measured for both antennas(main and diversity). With averaging, this measurement can be performedin less than 100 us to provide a fast and direct evaluation of how theantenna(s) is loaded. In one embodiment, device 100 can utilize a senseIC for antenna selection. In other embodiments, a feedback receiverintegrated in a transceiver IC can be utilized for obtaining thereflection measurements (or other measured parameters).

In one embodiment, communication device 100 can compare a current SenseIC reading (e.g., the complex input reflection coefficient) to a Sensereading that was recorded in freespace. The antenna selection criteriain this example can then be based on a difference between the currentloading conditions and freespace as determined in a Sense IC measurementplane.

In one embodiment, closed loop tuning can be performed by thecommunication device 100 and a comparison can be performed of aconverged grid location of the current antenna loading condition to agrid location for freespace. The antenna selection criteria in thisexample can then be based on a difference between the current loadingconditions and freespace as determined in the antenna plane.

In another embodiment, communication device 100 can use a converged gridlocation as described above. The antenna selection criteria in thisexample can then be based on a lookup table estimating antennaefficiency as a function of grid location. Depending on the antennacharacteristics, a scalar reflection measurement may be utilized.

The communication device 100 can include various components that arearranged in various configurations. The communication device 100 cancomprise one or more transceivers 102 coupled to an antenna system 101,which can be any number of antennas. As an example, each transceiver canhave transmitter and receiver sections herein described as transceiver102 or transceivers 102. The communication device 100 can have one ormore tunable circuits 122 including reactive element(s) 190, one or moretuning sensors 124, a user interface (UI) 104, a power supply 114, alocation receiver 116, a motion sensor 118, an orientation sensor 120,and/or a controller 106 for managing operations thereof. The transceiver102 can support short-range and/or long-range wireless accesstechnologies, including Bluetooth, ZigBee, Wireless Fidelity (WiFi),Digital Enhance Cordless Telecommunications (DECT), or cellularcommunication technologies, just to mention a few. The communicationdevice 100 can be a multi-mode device capable of providing communicationservices via various wireless access technologies, including two or moresuch services simultaneously.

Cellular technologies used by the communication device 100 can include,for example, Global System for Mobile (GSM), Code Division MultipleAccess (CDMA), Time Division Multiple Access (TDMA), Universal MobileTelecommunications (UMTS), World interoperability for Microwave (WiMAX),Software Defined Radio (SDR), Long Term Evolution (LTE), as well asother next generation wireless communication technologies as they arise.The transceiver 102 can also be adapted to support circuit-switchedwireline access technologies such as Public Switched Telephone Network(PSTN), packet-switched wireline access technologies such as TCP/IP,Voice over IP-VoIP, etc., or combinations thereof.

In one or more embodiments, dimensions, shapes and/or positions for thegroup of antennas of antenna system 101 can achieve a desiredperformance characteristic while fitting different mechanicalarrangements. These dimensions, shapes and/or positions can be adjustedto achieve other desired performance characteristic and/or for fittingother mechanical arrangements.

In one embodiment, the communication device 100 can include an RF switch150 (or other component) for switching the functionality of antennas ofthe antenna system 101 including switching primary antennas to diversityantennas and vice versa. For example, parameters of the communicationdevice 100 (e.g., reflection measurements for one, some or all of theantennas) can be monitored, detected or otherwise determined in order toidentify a change in impedance. The impedance change can result from achange in use case (e.g., switching from left hand to right hand to holdphone). The identification of the impedance change can trigger a changein the antenna system configuration via the RF switch 150 (e.g.,controlled by controller 106). The number of times this switch occurscan be based on the detected parameters, such as according to a userthat keeps switching hands during a communication session. The switchingof antennas can also be limited by a modem of the communication device100.

The tunable circuit 122 can comprise one or more variable reactiveelements such as variable capacitors, variable inductors, orcombinations thereof that are tunable with digital and/or analog biassignals. The tunable circuit 122 can represent a tunable matchingnetwork coupled to the antenna system 101 to compensate for a change inimpedance of the antenna 101, a compensation circuit to compensate formutual coupling in a multi-antenna system, an amplifier tuning circuitto control operations of an amplifier of the transceiver 102, a filtertuning circuit to alter a pass band of a filter used by the transceiver102, and so on. In one or more embodiments, the tunable circuit 122 canbe connected with one, some or all of the antennas of antenna system 101to enable impedance tuning.

In one or more embodiments, tuning sensors 124 can be placed at anystage of the transceiver 102 such as, for example, before or after amatching network, and/or at a power amplifier. The tuning sensors 124can utilize any suitable sensing technology such as directionalcouplers, voltage dividers, or other sensing technologies to measuresignals at any stage of the transceiver 102. The digital samples of themeasured signals can be provided to the controller 106 by way ofanalog-to-digital converters included in the tuning sensors 124. Dataprovided to the controller 106 by the tuning sensors 124 can be used tomeasure, for example, transmit power, transmitter efficiency, receiversensitivity, power consumption of the communication device 100,frequency band selectivity by adjusting filter passbands, linearity andefficiency of power amplifiers, specific absorption rate (SAR)requirements, and so on. The controller 106 can be configured to executeone or more tuning algorithms to determine desired tuning states of thetunable circuit 122 based on the foregoing measurements. The controller106 can also switch the primary and diversity antennas via RF switch 150based on data obtained from the tuning sensors 124, including based onreflection measurements.

The UI 104 can include a depressible or touch-sensitive keypad 108 witha navigation mechanism such as a roller ball, a joystick, a mouse, or anavigation disk for manipulating operations of the communication device100. The keypad 108 can be an integral part of a housing assembly of thecommunication device 100 or an independent device operably coupledthereto by a tethered wireline interface (such as a USB cable) or awireless interface supporting, for example, Bluetooth. The keypad 108can represent a numeric keypad commonly used by phones, and/or a QWERTYkeypad with alphanumeric keys. The UI 104 can further include a display110 such as monochrome or color LCD (Liquid Crystal Display), OLED(Organic Light Emitting Diode) or other suitable display technology forconveying images to an end user of the communication device 100. In anembodiment where the display 110 is touch-sensitive, a portion or all ofthe keypad 108 can be presented by way of the display 110 withnavigation features.

The display 110 can use touch screen technology to also serve as a userinterface for detecting user input. As a touch screen display, thecommunication device 100 can be adapted to present a user interface withgraphical user interface (GUI) elements that can be selected by a userwith a touch of a finger. The touch screen display 110 can be equippedwith capacitive, resistive or other forms of sensing technology todetect how much surface area of a user's finger has been placed on aportion of the touch screen display. This sensing information can beused to control the manipulation of the GUI elements or other functionsof the user interface. The display 110 can be an integral part of thehousing assembly of the communication device 100 or an independentdevice communicatively coupled thereto by a tethered wireline interface(such as a cable) or a wireless interface.

The UI 104 can also include an audio system 112 that utilizes audiotechnology for conveying low volume audio (such as audio heard inproximity of a human ear) and high volume audio (such as speakerphonefor hands free operation). The audio system 112 can further include amicrophone for receiving audible signals of an end user. The audiosystem 112 can also be used for voice recognition applications. The UI104 can further include an image sensor 113 such as a charged coupleddevice (CCD) camera for capturing still or moving images.

The power supply 114 can utilize common power management technologiessuch as replaceable and rechargeable batteries, supply regulationtechnologies, and/or charging system technologies for supplying energyto the components of the communication device 100 to facilitatelong-range or short-range portable applications. Alternatively, or incombination, the charging system can utilize external power sources suchas DC power supplied over a physical interface such as a USB port orother suitable tethering technologies.

The location receiver 116 can utilize location technology such as aglobal positioning system (GPS) receiver capable of assisted GPS foridentifying a location of the communication device 100 based on signalsgenerated by a constellation of GPS satellites, which can be used forfacilitating location services such as navigation. The motion sensor 118can utilize motion sensing technology such as an accelerometer, agyroscope, or other suitable motion sensing technology to detect motionof the communication device 100 in three-dimensional space. Theorientation sensor 120 can utilize orientation sensing technology suchas a magnetometer to detect the orientation of the communication device100 (north, south, west, and east, as well as combined orientations indegrees, minutes, or other suitable orientation metrics).

The communication device 100 can use the transceiver 102 to alsodetermine a proximity to or distance to cellular, WiFi, Bluetooth, orother wireless access points by sensing techniques such as utilizing areceived signal strength indicator (RSSI) and/or signal time of arrival(TOA) or time of flight (TOF) measurements.

The controller 106 can utilize computing technologies such as amicroprocessor, a digital signal processor (DSP), programmable gatearrays, application specific integrated circuits, and/or a videoprocessor with associated storage memory such as Flash, ROM, RAM, SRAM,DRAM or other storage technologies for executing computer instructions,controlling, and processing data supplied by the aforementionedcomponents of the communication device 100.

Other components not shown in FIG. 1 can be used by the subjectdisclosure. The communication device 100 can include a slot forinserting or removing an identity module such as a Subscriber IdentityModule (SIM) card. SIM cards can be used for identifying and registeringfor subscriber services, executing computer programs, storing subscriberdata, and so forth.

Referring to FIG. 2, a portion of a communication device 200 isillustrated. The device 200 can have any number of antennas, only two ofwhich are shown (210, 215). A Sense IC 220 can perform reflectionmeasurements that are used as feedback for closed loop antenna tuningvia one or both of tuners 222 and 223. An RF switch 250, which isdepicted as a DPDT switch, can be utilized for antenna selection so thatthe transmitter 202 can be routed to the antenna that has the mostfavorable loading conditions for radiation.

The reflection measurements from the Sense IC 224 can be used todetermine the loading conditions of each antenna 210, 215 and can beused as the selection criteria for the antenna selection. In one or moreembodiments, a feedback receiver (not shown) can be integrated in thetransceiver integrated circuit (e.g., in place of the Sense IC 224) forobtaining operational parameters such as the reflection measurements ofthe transmitting antenna.

The tuners 222 and/or 223 can utilize various tunable reactive elementsincluding capacitors and/or indictors. For example, tuners 222 and/or223 can include voltage or current tunable dielectric materials. Thetunable dielectric materials can utilize, among other things, acomposition of barium strontium titanate (BST). In another embodiment,the tunable reactive elements can utilize semiconductor varactors, ormicro-electromechanical systems (MEMS) technology capable ofmechanically varying the dielectric constant of a capacitor. Otherpresent or next generation methods or material compositions that resultin a voltage or current tunable reactive element are applicable to thesubject disclosure for use by the tuners 222 and/or 223.

Referring to FIG. 3A, a tuning grid 300 is illustrated that can be usedfor antenna selection by way of transmission Gamma measurements. Forexample, a grid location can be determined by a closed-loop tuningalgorithm and can be used as an input for the antenna selection. Forinstance, each grid location in a lookup table stored in thecommunication device 200 can have an entry for efficiency. In thisexample, the grid location can be determined by coarse tuning. Inanother example, the grid location can be further refined using finetuning. In one embodiment, a distance from the grid location to thefreespace antenna S11 location (referred to as FS_delta) can be utilizedfor the antenna selection. In another embodiment, instead of utilizingan algorithm-derived grid location, the communication device 200 canperform the antenna selection based directly on measurements from theSense IC 224.

Referring to FIGS. 3B and C, a schematic of a portion of a communicationdevice is illustrated along with corresponding Smith charts for thedevice's operation. The antenna S11 parameter for all use cases can beexamined in each band (or subband). For each band, a tuning grid in theantenna plane can be set or determined to sufficiently cover the entirerange of use cases. Γ_(ANT) is antenna S11 at the antenna plane. Γ_(OPT)is tuner S11 at the tuner input plane for each Γ_(ANT) with the optimaltuning state applied to the tuner for each Γ_(ANT). Γ_(OPT(SENSE)) isΓ_(OPT) as measured by the Sense IC at the Sense plane.

FIGS. 3B and C illustrate implementation of 2D tuning. The tuning domaincan be on a 2-dimensional grid in the Antenna Gamma space whichsufficiently covers all antenna uses cases. The grid can be rectangular,polar, or annular, and is not required to be uniform. Each grid locationcan correspond to the antenna gamma at the TX frequency. For each gridlocation, the antenna gamma at the RX frequency can be estimated basedon S-parameter characterization of the antenna. For each grid location,the tuner S-parameters can be evaluated at all tuning states and theoptimal tuning state (e.g., set of DAC values) can be recorded in atable or other data structure. There can be any number of DACs for eachtuning state, but the search can still be 2-dimensional in the gammaspace. The optimal or improved tuning state can be optimized or improvedfor TX, RX, both TX and RX, or other combinations such as carrieraggregation. A compromise between operational parameters and/or TX andRX mode can also be utilized during the tuning and/or antenna selection.

FIG. 3D illustrates a tuning grid established and utilized for bands 4and 5. The antenna S11 for all use cases can be examined in each band(or subband). For each band, a tuning grid in the antenna plane is setto sufficiently cover the entire range of use cases.

Referring to FIG. 3E, 2D tuning for a tuner with two voltage controlledcapacitors is illustrated. V1 and V2 can be determined in advance andstored in a lookup table in the communication device for each point inthe 2D, M×N grid. V1 and V2 can be restricted to the pairs listed in thetable. The tuning can be performed in the 2D grid space varying m and n.V1 and V2 can be retrieved from the lookup table based on the gridposition. In one embodiment, V1 and V2 cannot vary independently. M andn can be the two independent variables and V1 and V2 can be strictlydependent on m and n.

Referring to FIG. 3F, 2D tuning for a tuner with three voltagecontrolled capacitors is illustrated. V1, V2 and V3 can be determined inadvance and stored in a lookup table for each point in the 2D, M×N grid.V1, V2 and V3 can be restricted to the pairs listed in the table. Thetuning can be performed in the 2D grid space varying m and n. V1, V2 andV3 can be retrieved from the lookup table based on the grid position. Inone embodiment, V1, V2 and V3 cannot vary independently. M and n are thetwo independent variables and V1, V2 and V3 can be strictly dependent onm and n.

By utilizing 2D tuning rather than 3D tuning, even for three tunablereactance devices, the exemplary embodiment can avoid a failure ofconvergence and/or solutions trapped at local minima With 3D tuning,determined tuning values can have low reflection loss but highdissipative loss which is still undesired. The 2D tuning algorithm ofthe exemplary embodiments, filters out such lossy solutions for tuningvalues.

Referring to FIG. 4, a method 400 is illustrated for performing antennaselection in a communication device, such as the communication device200 of FIG. 2. Method 400 utilizes the Sense plane and FS_Delta forantenna selection.

At 402, the main tuner (e.g., tuner 222) can be connected with thecoupler. At 404, freespace DAC values can be applied to the main tunerand at 406 the reflection measurements can be obtained and recorded forthe primary antenna. At 408, the difference or delta can be determinedbetween the measured values and a pre-stored FS SENSE reference. Forexample, an FS reference can be stored for each individual unit by usinga factory calibration. The FS reference may include offsets forefficiency differences.

At 410, the diversity tuner (e.g., tuner 223) can be connected with thecoupler. At 412, freespace DAC values can be applied to the diversitytuner and at 414 the reflection measurements can be obtained andrecorded for the diversity antenna. At 416, the difference or delta canbe determined between the measured values and a pre-stored FS SENSEreference. At 418, the antenna with the smallest delta from the FSreference can be selected for transmitting. Method 400 can be repeatedduring a communication session since operating conditions can change,such as a user changing hands or interference patterns changing. In oneembodiment, the switching to a selected antenna is subject to permissionfrom the modem.

Referring to FIG. 5, a method 500 is illustrated for performing antennaselection in a communication device, such as the communication device200 of FIG. 2. Method 500 utilizes the antenna plane and FS Grid Deltafor antenna selection.

At 502, the main tuner (e.g., tuner 222) can be connected with thecoupler. At 504, freespace DAC values can be applied to the main tunerand at 506 the reflection measurements can be obtained and recorded forthe primary antenna.

At 507, tuning, such as coarse tuning, can be performed and/or thetuning grid (e.g., grid 300) can be calculated for the coarse tune. At508, the difference or delta can be determined between the location ofthe tuning grid and a FS location on the tuning grid. In one embodiment,antenna selection can be performed based on the determined delta, suchas satisfying a threshold. In another embodiment, method 500 can proceedfrom 508 to 510 without switching antennas.

At 510, the diversity tuner (e.g., tuner 223) can be connected with thecoupler. At 512, freespace DAC values can be applied to the diversitytuner and at 514 the reflection measurements can be obtained andrecorded for the diversity antenna. At 515, tuning, such as coarsetuning, can be performed and/or the tuning grid (e.g., grid 300) can becalculated for the coarse tune. At 516, the difference or delta can bedetermined between the location of the tuning grid and a FS location onthe tuning grid. At 518, the antenna with the smallest grid delta fromthe FS reference location can be selected for transmitting. Method 500can be repeated during a communication session since operatingconditions can change, such as a user changing hands or interferencepatterns changing. In one embodiment, the switching to a selectedantenna is subject to permission from the modem.

As a further example of method 500 and referring additionally to FIG. 6,a portion of a communication device 600 is illustrated. Device 600 caninclude switchable primary and diversity antennas 610, 615. Radiationefficiency between the antennas 610, 615 can be different based on anumber of factors, such as which user hand is holding the phone and soforth. Reflection measurement data is illustrated In FIGS. 7 and 8 forthe main and diversity antennas 610, 615 for different use cases (e.g.,BHHR and BHHL) in different frequency bands. The Smith charts depict thedistance or delta between the location on the Smith chart and a locationcorresponding to free space. In some instance, differentiating betweendifferent use cases based solely on reflection measurements can bedifficult. In one or more embodiments, other information or inputs canbe utilized to facilitate distinguishing the use cases. For example, aproximity sensor can be utilized to gather proximity data that can beutilized in distinguishing between use cases (e.g., BHHR vs Freespace).In another example, capacitive information, such as from a capacitivesensor attached to one, some or all of the antennas or from a capacitivesensor attached to the touch screen, can be utilized in distinguishingbetween the use cases. Other inputs can also be used in facilitatingdistinguishing between use cases, such as the operational frequencyrange. In these examples, reflection measurements and other obtainedinformation can be utilized for the antenna selection and/or forimpedance tuning.

Referring to FIG. 9, radiation efficiency for the main and diversityantennas at different frequencies in a lowband according to differentuse cases is illustrated based on a calculation of subtracting mismatchloss from antenna efficiency.

FIG. 10 illustrates antenna selection by applying the process of method500 according to FS_delta criteria. As shown in FIG. 10, other inputs,such as the operating frequency range can be utilized in combinationwith the reflection measurements to facilitate in distinguishing betweendifferent use cases. The other inputs are not limited to frequency data,and can include proximity information from a proximity sensor,capacitive data from a capacitive sensor (e.g., attached to the antennaor attached to a touch screen), and so forth.

Referring to FIG. 11, radiation efficiency for the main and diversityantennas at different frequencies in a mid/highband according todifferent use cases is illustrated based on a calculation of subtractingmismatch loss from antenna efficiency. FIG. 12 illustrates antennaselection by applying the process of method 500 according to FS_deltacriteria.

Referring to FIG. 13, a method 1300 is illustrated for performingantenna selection in a communication device, such as the communicationdevice 200 of FIG. 2. Method 1300 utilizes the antenna plane and anefficiency lookup table for antenna selection.

At 1302, the main tuner (e.g., tuner 222) can be connected with thecoupler. At 1304, freespace DAC values can be applied to the main tunerand at 1306 the reflection measurements can be obtained and recorded forthe primary antenna.

At 1307, tuning, such as coarse tuning, can be performed and/or thetuning grid (e.g., grid 300) can be calculated for the coarse tune. At1308, the antenna efficiency can be determined by looking it up in alookup table according to the grid location. As described earlier withrespect to tuning grid 300, each grid location can have an entry in alookup table for efficiency. The grid location can be determined bycoarse tuning and/or the grid location can be further refined using finetuning.

At 1310, the diversity tuner (e.g., tuner 223) can be connected with thecoupler. At 1312, freespace DAC values can be applied to the diversitytuner and at 514 the reflection measurements can be obtained andrecorded for the diversity antenna. At 1315, tuning, such as coarsetuning, can be performed and/or the tuning grid (e.g., grid 300) can becalculated for the coarse tune. At 1316, the antenna efficiency can bedetermined by looking it up in a lookup table according to the gridlocation. At 1318, the antenna with the higher efficiency can beselected for transmitting. Method 1300 can be repeated during acommunication session since operating conditions can change, such as auser changing hands or interference patterns changing. In oneembodiment, the switching to a selected antenna is subject to permissionfrom the modem.

Referring to FIG. 14, a table 1400 is illustrated which can be used forantenna selection. For this example and further referring tocommunication device 200 of FIG. 2, the device can be transmitting onantenna 215 as the primary antenna. A closed loop tuning algorithm forantenna 215 can be executed by a processor of device 200 utilizing theSense IC 224. In one embodiment, antenna 210 can be operating as thediversity antenna, which can be executing an open loop tuning algorithm.

In this example, during the closed loop algorithm State 0-1 (OL), theantenna selection bit can be set as AntSel=0 (don't switch). During theclosed loop algorithm states 2-n (e.g., n=13), the current grid winnercan be compared to RealIndSW and ImagIndSw and the nearest use case canbe determined. The antenna selection bit can be updated based on theSwAnt value in the table for the nearest use case. In this example, whenthe modem permits switching antennas (RX_ON) the following is applied:

-   -   If AntSel=0, then do not switch. Continue closed loop algorithm.    -   If AntSel=1: switch antennas; apply RX DACs to main antenna; and        apply DX DACs to diversity antenna.

Referring to FIG. 15, a table 1500 is illustrated which can be used forantenna selection. For this example and further referring tocommunication device 200 of FIG. 2, the device can be transmitting onantenna 210. When transmitting on antenna 210, the processor of thedevice 200 can switch from an open loop tuning algorithm to a closedloop tuning algorithm utilizing the Sense IC 224. The closed loop tuningalgorithm can utilize coarse tuning. In this example, when transmittingon antenna 210, the processor can continue to perform reflectionmeasurements readings (via the Sense IC 224) at a same rate as used inthe closed loop algorithm on antenna 215.

The Sense IC reading can be compared by the processor to each gamma_UCto find a nearest use case. In one embodiment, a Sense IC validity checkcan be performed according to obtaining consecutive readings within 0.1.The processor can update the tuning based on a derived use case. Theprocessor can update the antenna selection bit based on SwAnt value inthe table for the nearest use case. In one embodiment, when the modempermits switching antennas (RX_ON), the following can be applied:

-   -   If AntSel=0, then do not switch. Continue applying coarse tuning        algorithm on diversity.    -   If AntSel=1, switch antennas; apply RX DACs to diversity        antenna; and apply DX DACs to main Antenna.

In one or more embodiments, the switching of antennas can causedifferent tuning to be applied to the different antennas. For example ina two antenna system where an antenna switch occurs (e.g., via RF switch250 of FIG. 2), one of the antennas can switch from a main antenna to adiversity antenna while the other antenna can switch from the diversityantenna to the main antenna. By switching roles, the antennas alsoswitch functions from a combination of transmit and receive functions toa receive-only function, and vice versa. The switching of functions cancause switching of tuning states for each of the antennas. For instance,the antenna which is now only a receive antenna can be tuned to optimizeor otherwise improve receiving via a first tunable reactance circuitwhile the antenna which is now both a transmit and receive antenna canbe tuned for a compromise between improving receiving and improvingtransmitting via a second tunable reactance circuit.

In one or more embodiments, different tuning values can be utilizedwithout changing antennas according to whether the particular antenna isset to optimize receiving or whether the particular antenna is set tocompromise between transmit and receive. For instance, while an antennais in the receive mode a first set of tuning values can be utilized viathe RX DAC's and while the antenna is in a transmit mode a second set oftuning values can be utilized via the duplex DAC's.

Referring to FIG. 16, a portion of a communication device 1600 isillustrated which can utilize antenna selection based on operationalparameters obtained from a Sense IC 1624. Various other components canbe utilized to facilitate the capturing and analysis of operationalparameters (e.g., reflection measurements) including directionalcouplers, as well as to facilitate the switching antennas, such asswitches 1650. In one embodiment, device 1600 can measure power coupledto the other antennas to estimate absorption. For example, the followingmeasurements can be performed:Measure LB1 to MB1(P_L1M1=L1_INC−M1_DEL)Measure LB2 to MB1(P_L2M1=L2_INC−M1_DEL)Measure LB1 to MB2(P_L1M2=L1_INC−M2_DEL)Measure LB2 to MB2(P_L2M2=L2_INC−M2_DEL)

A freespace 2×2 characterization can be employed to determine acalibration matrix. Absorption can then be calculated according to thefollowing:ABS11=P_L1M1−P_L1M1_FSABS21=P_L2M1−P_L2M1_FSABS12=P_L1M2−P_L1M2_FSABS22=P_L2M2−P_L2M2_FS

In one or more embodiments, less than all of the measurements may beperformed, such as measurements of only two of the four paths in thisexample. In one embodiment, if the MB operation includes tuning, thetuning can be specifically set for LB operation. This example makes useof the HB antenna(s) to perform the transmission measurements.Alternatively, a strategically located, separate antenna may be used.

Referring to FIG. 17, a method 1700 is illustrated for performingantenna selection according to transmission measurements. Method 1700can operate utilizing an antenna plane delta. At 1702,

At 1702, connect the LB Main tuner to the coupler. At 1704, performcoarse tuning, such as to improve or optimize the match. At 1706,measure any coupling to the MB/HB1 and/or MB/HB2 antennas. At 1710,connect the LB diversity tuner to the coupler. At 1712, perform coarsetuning. At 1714, measure any coupling to the MB/HB1 and/or MB/HB2antennas. At 1716, determine which antenna has least absorption andbased the antenna selection on this determination.

FIG. 18 depicts an illustrative embodiment of a portion of the wirelesstransceiver 102 of the communication device 100 of FIG. 1. In GSMapplications, the transmit and receive portions of the transceiver 102can include amplifiers 1801, 1803 coupled to a tunable matching network1802 that is in turn coupled to an impedance load 1806 (which can be oneor more antennas including primary and diversity antennas). Antennaswitching, via switch 150, can be performed based on operationalparameters associated with one, some, or all of the antennas, such asbased on reflection measurements.

In one or more embodiments, a full duplex configuration without switch1804 can be utilized such as for an LTE or WCDMA application. Thetunable matching network 1802 can include all or a portion of the tuningcircuit 122 of FIG. 1, such as variable capacitors to enable highlinearity tuning while satisfying performance criteria such as insertionloss thresholds and/or response time speed. The impedance load 1806 inthe present illustration can be all or a portion of the antenna system(e.g., reconfigurable via RF switch 150) as shown in FIG. 1 (hereinantenna 1806). In one or more embodiments, the RF switch 150 can be onthe Tx/Rx side of the matching network(s) 1802. In another embodiment, aseparate matching network 1802 can be used for each antenna. A transmitsignal in the form of a radio frequency (RF) signal (TX) can be directedto the amplifier 1801 which amplifies the signal and directs theamplified signal to the antenna 1806 by way of the tunable matchingnetwork 2018 when switch 1804 is enabled for a transmission session. Thereceive portion of the transceiver 102 can utilize a pre-amplifier 1803which amplifies signals received from the antenna 1806 by way of thetunable matching network 1802 when switch 1804 is enabled for a receivesession. Other configurations of FIG. 18 are possible for other types ofcellular access technologies such as CDMA, UMTS, LTE, and so forth. Theexemplary embodiments are applicable to all types of radio technologiesincluding WiFi, GPS and so forth, and are not intended to be limited tocellular access technologies. These undisclosed configurations areapplicable to the subject disclosure.

FIGS. 19-20 depict illustrative embodiments of the tunable matchingnetwork 1802 of the transceiver 102 of FIG. 18. In one embodiment, thetunable matching network 1802 can comprise a control circuit 302 and atunable reactive element 1910. The control circuit 1902 can comprise aDC-to-DC converter 1904, one or more digital to analog converters (DACs)1906 and one or more corresponding buffers 1908 to amplify the voltagegenerated by each DAC. The amplified signal can be fed to one or moretunable reactive components 404, 406 and 408 such as shown in FIG. 4,which depicts a possible circuit configuration for the tunable reactiveelement 310. In this illustration, the tunable reactive element 310includes three tunable capacitors 2004-2008 and two inductors 2002-2003with a fixed inductance. Circuit configurations such as “Tee”, “Pi”, and“L” configurations for a matching circuit are also suitableconfigurations that can be used in the subject disclosure.

The tunable capacitors 2004-2008 can each utilize technology thatenables tunability of the reactance of the component. One embodiment ofthe tunable capacitors 2004-2008 can utilize voltage or current tunabledielectric materials. The tunable dielectric materials can utilize,among other things, a composition of barium strontium titanate (BST). Inanother embodiment, the tunable reactive element 310 can utilizesemiconductor varactors, or micro-electromechanical systems (MEMS)technology capable of mechanically varying the dielectric constant of acapacitor. Other present or next generation methods or materialcompositions that result in a voltage or current tunable reactiveelement are applicable to the subject disclosure for use by the tunablereactive element 1910 of FIG. 19.

The DC-to-DC converter 1904 can receive a DC signal such as 3 volts fromthe power supply 114 of the communication device 100 in FIG. 1A. TheDC-to-DC converter 1904 can use technology to amplify a DC signal to ahigher range (e.g., 30 volts) such as shown. The controller 106 cansupply digital signals to each of the DACs 1906 by way of a control bus1907 of “n” or more wires or traces to individually control thecapacitance of tunable capacitors 2004-2008, thereby varying thecollective reactive impedance of the tunable matching network 202. Thecontrol bus 1907 can be implemented with a two-wire serial bustechnology such as a Serial Peripheral Interface (SPI) bus (referred toherein as SPI bus 1907). With an SPI bus 1907, the controller 106 cantransmit serialized digital signals to configure each DAC in FIG. 19.The control circuit 1902 of FIG. 19 can utilize digital state machinelogic to implement the SPI bus 1907, which can direct digital signalssupplied by the controller 106 to the DACs to control the analog outputof each DAC, which is then amplified by buffers 1908. In one embodiment,the control circuit 1902 can be a stand-alone component coupled to thetunable reactive element 1910. In another embodiment, the controlcircuit 1902 can be integrated in whole or in part with another devicesuch as the controller 106.

Although the tunable reactive element 1910 is shown in a unidirectionalfashion with an RF input and RF output, the RF signal direction isillustrative and can be interchanged. Additionally, either port of thetunable reactive element 1910 can be connected to a feed point of theantenna 1806, a structural element of the antenna 1806 in an on-antennaconfiguration, or between antennas for compensating mutual coupling whendiversity antennas are used, or when antennas of differing wirelessaccess technologies are physically in close proximity to each other andthereby are susceptible to mutual coupling. The tunable reactive element1910 can also be connected to other circuit components of a transmitteror a receiver section such as filters, amplifiers, and so on, to controloperations thereof.

In another embodiment, the tunable matching network 1802 of FIG. 18 cancomprise a control circuit 2102 in the form of a decoder and a tunablereactive element 2104 comprising switchable reactive elements such asshown in FIG. 6. In this embodiment, the controller 106 can supply thecontrol circuit 2102 signals via the SPI bus 1907, which can be decodedwith Boolean or state machine logic to individually enable or disablethe switching elements 2202. The switching elements 2202 can beimplemented with semiconductor switches, MEMS, or other suitableswitching technology. By independently enabling and disabling thereactive elements 2204 (capacitor or inductor) of FIG. 22 with theswitching elements 2202, the collective reactive impedance of thetunable reactive element 2104 can be varied by the controller 106.

The tunable reactive elements 1910 and 2104 of FIGS. 19 and 21,respectively, can be used with various circuit components of thetransceiver 102 to enable the controller 106 to manage performancefactors such as, for example, but not limited to, transmit power,transmitter efficiency, receiver sensitivity, power consumption of thecommunication device 100, frequency band selectivity by adjusting filterpassbands, linearity and efficiency of power amplifiers, SARrequirements, among other operational parameters.

FIG. 23 depicts an illustration of a look-up table stored in memory,which can be indexed by the controller 106 of the communication device100 of FIG. 1 according to physical and/or functional use cases of thecommunication device 100. The desired tuning state can include valuesfor the biasing signals and/or capacitance values to be employed fortuning of the variable capacitors, such as BST variable capacitors. Aphysical use case can represent a physical state of the communicationdevice 100, while a functional use case can represent an operationalstate of the communication device 100. For example, for a flip phone2400 of FIG. 24, an open flip can represent one physical use case, whilea closed flip can represent another physical use case. In a closed flipstate (i.e., bottom and top flips 2402-2404 are aligned), a user islikely to have his/her hands surrounding the top flip 2404 and thebottom flip 2402 while holding the phone 2400, which can result in onerange of load impedances experienced by an internal or retrievableantenna (not shown) of the phone 2400. The range of load impedances ofthe internal or retrievable antenna can be determined by empiricalanalysis.

With the flip open a user is likely to hold the bottom flip 2402 withone hand while positioning the top flip 2404 near the user's ear when anaudio system of the phone 2400, such audio system 112 of FIG. 1, is setto low volume, and voice channel is active. If, on the other hand, theaudio system 112 is in speakerphone mode, it is likely that the user ispositioning the top flip 2404 away from the user's ear. In thesearrangements, different ranges of load impedances can be experienced bythe internal or retrievable antenna, which can be analyzed empirically.The low and high volume states of the audio system 112, as well as, adetermination that a voice channel is active, illustrates varyingfunctional use cases.

For a phone 2500 with a slideable keypad 2504 (illustrated in FIG. 25),the keypad in an outward position can present one range of loadimpedances of an internal antenna, while the keypad in a hidden positioncan present another range of load impedances, each of which can beanalyzed empirically. For a smartphone 2600 (illustrated in FIG. 26)presenting a video game, an assumption can be made that the user islikely to hold the phone away from the user's ear in order to view thegame. Placing the smartphone 2600 in a portrait position 2602 canrepresent one physical and operational use case, while utilizing thesmartphone 2600 in a landscape position 1004 presents another physicaland operational use case.

The number of hands and fingers used in the portrait mode may bedetermined by the particular type of game being played by the user. Forexample, a particular video game may require a user interface where asingle finger in portrait mode may be sufficient for controlling thegame. In this scenario, it may be assumed that the user is holding thesmartphone 2600 in one hand in portrait mode and using a finger with theother. By empirical analysis, a possible range of impedances of theinternal antenna(s) of the communication device can be determined whenusing the video game in portrait mode. Similarly, if the video gameselected has a user interface that is known to require two hands inlandscape mode, another estimated range of impedances of the internalantenna can be determined empirically.

A multimode phone 2700 capable of facilitating multiple accesstechnologies such as GSM, CDMA, LTE, WiFi, GPS, and/or Bluetooth in twoor more combinations can provide additional insight into possible rangesof impedances experienced by two or more internal antennas of themultimode phone 2700. For example, a multimode phone 2700 that providesGPS services by processing signals received from a constellation ofsatellites 2702, 2704 can be empirically analyzed when other accesstechnologies are also in use. Suppose, for instance, that whilenavigation services are enabled, the multimode phone 2700 isfacilitating voice communications by exchanging wireless messages with acellular base station 2706. In this state, an internal antenna of theGPS receiver may be affected by a use case of a user holding themultimode phone 2700 (e.g., near the user's ear or away from the user'sear). The effect on the GPS receiver antenna and the GSM antenna by theuser's hand position can be empirically analyzed.

Suppose in another scenario that the antenna of a GSM transceiver is inclose proximity to the antenna of a WiFi transceiver. Further assumethat the GSM frequency band used to facilitate voice communications isnear the operational frequency of the WiFi transceiver. Also assume thata use case for voice communications may result in certain physicalstates of the multimode phone 2700 (e.g., slider out), which can resultin a probable hand position of the user of the multimode phone 2700.Such a physical and functional use case can affect the impedance rangeof the antenna of the WiFi transceiver as well as the antenna of the GSMtransceiver.

A close proximity between the WiFi and GSM antennas and the nearoperational frequency of the antennas may also result in cross-couplingbetween the antennas. Mutual or cross-coupling under these circumstancescan be measured empirically. Similarly, empirical measurements of theimpedances of other internal antennas can be measured for particularphysical and functional use configurations when utilizing Bluetooth,WiFi, Zigbee, or other access technologies in peer-to-peercommunications with another communication device 2708 or with a wirelessaccess point 2710. In diversity designs such as multiple-input andmultiple output (MIMO) antennas, physical and functional use cases of acommunication device can be measured empirically to determine how bestto configure a tunable compensation circuit 122 such as shown in FIG. 1.

The number of physical and functional use cases of a communicationdevice 100 can be substantial when accounting for combinations of accesstechnologies, frequency bands, antennas of different accesstechnologies, antennas configured for diversity designs, and so on.These combinations, however, can be empirically analyzed to determineload impedances of the antenna(s), mutual coupling between them, and theeffects on transmitter and receiver performance metrics. Mitigationstrategies to reduce mutual coupling, counter the effect of varying loadimpedances, and to improve other performance metrics of the transceiver102 can also be determined empirically. The empirical data collected andcorresponding mitigation strategies can be recorded in the look-up tableof FIG. 23 and indexed according to combinations of physical andfunctional use cases detected by the communication device 100. Theinformation stored in the look-up table can be used in open-loop RFtuning applications to initialize tunable circuit components of thetransceiver 102, as well as, tuning algorithms that control operationalaspects of the tunable circuit components.

In one or more embodiments, information in the look-up table of FIG. 23can be used for impedance tuning in conjunction with re-configuring orswitching the primary and diversity antennas.

Other embodiments can be applied to the subject disclosure withoutdeparting from the scope of the claims described below.

It should be understood that devices described in the exemplaryembodiments can be in communication with each other via various wirelessand/or wired methodologies. The methodologies can be links that aredescribed as coupled, connected and so forth, which can includeunidirectional and/or bidirectional communication over wireless pathsand/or wired paths that utilize one or more of various protocols ormethodologies, where the coupling and/or connection can be direct (e.g.,no intervening processing device) and/or indirect (e.g., an intermediaryprocessing device such as a router).

Radio band information can be generally available or otherwiseretrievable in communication devices, which provides the broadestdefinition of where in a frequency spectrum a communication device suchas a handset is operating (e.g., transmitting). In communication systems(e.g., cellular systems), frequencies can be commonly allocated forusage in a block or range of frequencies. This block or range offrequencies is commonly known as a radio band. Multiple radio bands canbe present in any given cellular system, and in any geographic locationthere can be multiple cellular systems present.

A radio channel can identify a discrete set of frequencies in a cellularsystem that contains the downlink (from base station to the handset) anduplink (from handset to base station) radio signals. Downlink is alsoreferred to as Rx and uplink is also referred to as Tx. In most systems,such as WCDMA (Wideband Code Division Multiple Access), uplink anddownlink can use separate frequencies that are separated by the duplexdistance, which is the number of Hz separating the uplink and downlinkpaths. For other systems, such as TD-LTE (Time Division Long TermEvolution), the uplink and downlink can use the same frequency.

One or more of the exemplary embodiments can utilize radio bandinformation, including only radio band information in some embodimentsor radio band information in combination with other information (e.g.,measured operational parameters), for antenna tuning. The exemplaryembodiments can apply to various types of devices, including wirelesshandsets operating utilizing one or more of various communicationprotocols.

RF tuning based on limited information, such as only the radio band, cancreate a number of problems. In an ideal cellular system that employs RFtuning, the tuner would be set to match every frequency on which theradio receives or transmits, with the understanding that typically asingle antenna is used for both Rx and Tx which requires the RF tuner tochange tuning state as the RF signal on the antenna changes frequency.For half-duplex systems, such as GSM that would be for every Rx and Tx,including neighbor cells. In full-duplex systems, such as WCDMA whereboth Rx and Tx are present concurrently, the RF tuner has to change whenthe frequency changes for handoffs and neighbor cell monitoring, andadditionally the tuning state has to be a duplex setting for Rx and Txon a frequency between the Rx and Tx frequencies.

In order to perform RF tuning in such an ideal system, the entitycontrolling the tuner could require exact knowledge in real time of allrelevant information pertaining to operating the tuner, such as theradio timing, radio band, radio channel, RF duplex information, andtransmit state. Tuning based on limited information occurs when theentity controlling the tuner does not have all the information requiredto set the RF tuner to match an exact frequency at a given time. Forexample, real time channel information could be missing, in which casethe tuner control entity could set the RF tuner based on informationpertaining to the Radio Band only.

Transmit (Tx) and Receive (Rx) operations often cannot or are not tunedin real-time. This can result in or necessitate a broader duplex typetuning Duplex tuning refers to where the tunable element for aparticular sub-band or radio channel is tuned to a frequency betweenuplink and downlink; one tuning state can be used for both Rx and Tx inthis case. In some systems that are full-duplex (concurrent uplink anddownlink, such as WCDMA), duplex tuning is commonly used. Other systemsthat are half-duplex (uplink and downlink are not concurrent, such asGSM), the tuner can be tuned for both Rx and Tx.

Sub-band describes a grouping of frequencies (e.g., radio channels)consisting of one or more radio channels. In tuning applications,sub-dividing a radio band into multiple sub-bands can provide theadvantage of being able to apply a particular tuning state to a small orsmaller range of radio channels. Sub-bands can be used in conjunctionwith storage and application of calibration data in cellular handsets,providing a compromise between accuracy and amount of storage needed tohold said calibration data.

An example of a radio band is the GSM 900 band, in which the uplinkfrequencies can occupy the range 880.0 to 915.0 MHz and the downlinkfrequencies can occupy the range 925.0 to 960.0 MHz. The duplex spacingcan be 45 MHz. The first channel can be channel 975 which has uplink at880.2 MHz and downlink at 915.2 MHz. The last channel can be channel 124which has uplink at 914.8 MHz and downlink at 959.8 MHz.

The GSM 900 band can, for example, be subdivided into 3 sub bands asfollows: Sub band 1 ranging from channel 975 to channel 1023 (48channels, 9.6 MHz wide), Sub Band 2 ranging from channel 0 to channel 66(66 channels, 13.2 MHz wide), and sub band 3 ranging from channel 67 tochannel 124 (57 channels, 11.4 MHz wide). This is an example of a radioband and sub-bands, and the present disclosure can include variousconfigurations of radio bands and sub-bands.

Similar principles can be applied to other existing wireless accesstechnologies (e.g., UMTS, etc.) as well as future generation accesstechnologies.

FIG. 28 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system 2800 within which a set of instructions,when executed, may cause the machine to perform any one or more of themethods discussed above. One or more instances of the machine canoperate, for example, as the communication device 100 or other devicesdescribed herein for performing antenna selection and/or impedancetuning in a multi-antenna device. In some embodiments, the machine maybe connected (e.g., using a network 2826) to other machines. In anetworked deployment, the machine may operate in the capacity of aserver or a client user machine in server-client user networkenvironment, or as a peer machine in a peer-to-peer (or distributed)network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a smart phone, a laptop computer, adesktop computer, a control system, a network router, switch or bridge,or any machine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a communication device of the subject disclosureincludes broadly any electronic device that provides voice, video ordata communication. Further, while a single machine is illustrated, theterm “machine” shall also be taken to include any collection of machinesthat individually or jointly execute a set (or multiple sets) ofinstructions to perform any one or more of the methods discussed herein.

The computer system 2800 may include a processor (or controller) 2802(e.g., a central processing unit (CPU), a graphics processing unit (GPU,or both), a main memory 2804 and a static memory 2806, which communicatewith each other via a bus 2808. The computer system 2800 may furtherinclude a display unit 2810 (e.g., a liquid crystal display (LCD), aflat panel, or a solid state display. The computer system 2800 mayinclude an input device 2812 (e.g., a keyboard), a cursor control device2814 (e.g., a mouse), a disk drive unit 2816, a signal generation device2818 (e.g., a speaker or remote control) and a network interface device2820. In distributed environments, the embodiments described in thesubject disclosure can be adapted to utilize multiple display units 2810controlled by two or more computer systems 2800. In this configuration,presentations described by the subject disclosure may in part be shownin a first of the display units 2810, while the remaining portion ispresented in a second of the display units 2810.

The disk drive unit 2816 may include a tangible computer-readablestorage medium 2822 on which is stored one or more sets of instructions(e.g., software 2824) embodying any one or more of the methods orfunctions described herein, including those methods illustrated above.The instructions 2824 may also reside, completely or at least partially,within the main memory 2804, the static memory 2806, and/or within theprocessor 2802 during execution thereof by the computer system 2800. Themain memory 2804 and the processor 2802 also may constitute tangiblecomputer-readable storage media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the subject disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

While the tangible computer-readable storage medium 2822 is shown in anexample embodiment to be a single medium, the term “tangiblecomputer-readable storage medium” should be taken to include a singlemedium or multiple media (e.g., a centralized or distributed database,and/or associated caches and servers) that store the one or more sets ofinstructions. The term “tangible computer-readable storage medium” shallalso be taken to include any non-transitory medium that is capable ofstoring or encoding a set of instructions for execution by the machineand that cause the machine to perform any one or more of the methods ofthe subject disclosure.

The term “tangible computer-readable storage medium” shall accordinglybe taken to include, but not be limited to: solid-state memories such asa memory card or other package that houses one or more read-only(non-volatile) memories, random access memories, or other re-writable(volatile) memories, a magneto-optical or optical medium such as a diskor tape, or other tangible media which can be used to store information.Accordingly, the disclosure is considered to include any one or more ofa tangible computer-readable storage medium, as listed herein andincluding art-recognized equivalents and successor media, in which thesoftware implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are from time-to-timesuperseded by faster or more efficient equivalents having essentiallythe same functions. Wireless standards for device detection (e.g.,RFID), short-range communications (e.g., Bluetooth, WiFi, Zigbee), andlong-range communications (e.g., WiMAX, GSM, CDMA, LTE) are contemplatedfor use by computer system 2800.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

Although specific embodiments have been illustrated and describedherein, it should be appreciated that any arrangement calculated toachieve the same purpose may be substituted for the specific embodimentsshown. This disclosure is intended to cover any and all adaptations orvariations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,can be used in the subject disclosure. In one or more embodiments,features that are positively recited can also be excluded from theembodiment with or without replacement by another component or step. Thesteps or functions described with respect to the exemplary processes ormethods can be performed in any order. The steps or functions describedwith respect to the exemplary processes or methods can be performedalone or in combination with other steps or functions (from otherembodiments or from other steps that have not been described). Less thanall of the steps or functions described with respect to the exemplaryprocesses or methods can also be performed in one or more of theexemplary embodiments. Further, the use of numerical terms to describe adevice, component, step or function, such as first, second, third, andso forth, is not intended to describe an order or function unlessexpressly stated so. The use of the terms first, second, third and soforth, is generally to distinguish between devices, components, steps orfunctions unless expressly stated otherwise. Additionally, one or moredevices or components described with respect to the exemplaryembodiments can facilitate one or more functions, where the facilitating(e.g., facilitating access or facilitating establishing a connection)can include less than every step needed to perform the function or caninclude all of the steps needed to perform the function.

In one or more embodiments, a processor (which can include a controlleror circuit) has been described that performs various functions. Itshould be understood that the processor can be multiple processors,which can include distributed processors or parallel processors in asingle machine or multiple machines. The processor can include virtualprocessor(s). The processor can include a state machine, applicationspecific integrated circuit, and/or programmable gate array including aField PGA, or state machine. In one or more embodiments, when aprocessor executes instructions to perform “operations”, this caninclude the processor performing the operations directly and/orfacilitating, directing, or cooperating with another device or componentto perform the operations.

The Abstract of the Disclosure is provided with the understanding thatit will not be used to interpret or limit the scope or meaning of theclaims. In addition, in the foregoing Detailed Description, it can beseen that various features are grouped together in a single embodimentfor the purpose of streamlining the disclosure. This method ofdisclosure is not to be interpreted as reflecting an intention that theclaimed embodiments require more features than are expressly recited ineach claim. Rather, as the following claims reflect, inventive subjectmatter lies in less than all features of a single disclosed embodiment.Thus the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separately claimedsubject matter.

What is claimed is:
 1. A mobile communication device, comprising: atransceiver; an antenna system coupled with the transceiver, wherein theantenna system includes a first antenna and a second antenna, whereinone of the first or second antennas is operating as a primary antennaand another of the first or second antennas is operating as a diversityantenna; an RF switch connected with the antenna system, wherein the RFswitch has a first position in which the first antenna is the primaryantenna and the second antenna is the diversity antenna, and wherein theRF switch has a second position in which the second antenna is theprimary antenna and the first antenna is the diversity antenna; amatching network coupled with the transceiver and the antenna system,wherein the matching network comprises a tunable reactive element; and acontroller coupled with the matching network and with the RF switch,wherein the controller receives first reflection measurements associatedwith the antenna system, wherein the controller adjusts the tunablereactive element according to the first reflection measurements toprovide impedance tuning, wherein the controller adjusts the RF switchto select between the first and second positions according to the firstreflection measurements, wherein the controller adjusts the RF switch toselect between the first and second positions according to the firstreflection measurements and a distance measured from free spacedesignated on a stored tuning grid.
 2. The mobile communication deviceof claim 1, further comprising a modem, wherein the controller adjuststhe RF switch to select between the first and second positions during atime period in which the modem enables an antenna switch.
 3. The mobilecommunication device of claim 1, wherein the first reflectionmeasurements are limited to one of the first or second antennas.
 4. Themobile communication device of claim 1, wherein the RF switch is in thefirst position, wherein the first reflection measurements are limited tothe first antenna, wherein the controller adjusts the RF switch toselect the second position according to the first reflectionmeasurements, wherein the controller receives second reflectionmeasurements that are limited to the second antenna, wherein thecontroller adjusts the tunable reactive element according to the secondreflection measurements to provide the impedance tuning.
 5. The mobilecommunication device of claim 4, wherein the controller adjusts the RFswitch to select the first position according to the second reflectionmeasurements.
 6. The mobile communication device of claim 1, wherein thecontroller adjusts the RF switch to select between the first and secondpositions according to the first reflection measurements and a storedfree space reference value.
 7. The mobile communication device of claim1, wherein the adjusting of the RF switch to select between the firstand second positions is based on a stored efficiency value correspondingto a location on the tuning grid.
 8. The mobile communication device ofclaim 1, wherein the impedance tuning is for the first and secondantennas, wherein the tunable reactive element comprises a first tunablereactive element and a second tunable reactive element, wherein thefirst tunable reactive element performs the impedance tuning for thefirst antenna, and wherein the second tunable reactive element performsthe impedance tuning for the second antenna.
 9. A method comprising:obtaining, by a controller of a communication device, first reflectionmeasurements for a first antenna of the communication device operatingas a primary antenna when an RF switch of the communication device is ina first position; adjusting, by the controller, a tunable reactiveelement of a matching network according to the first reflectionmeasurements to perform impedance tuning; analyzing, by the controller,the first reflection measurements to determine a desired antenna fortransmission; switching, by the controller, the RF switch to a secondposition responsive to a determination that a second antenna of thecommunication device is the desired antenna for transmission, whereinthe switching to the second position causes the second antenna tooperate as the primary antenna; obtaining, by the controller, secondreflection measurements for the second antenna operating as the primaryantenna when the RF switch is in the second position; adjusting, by thecontroller, the tunable reactive element according to the secondreflection measurements to perform the impedance tuning; analyzing, bythe controller, the second reflection measurements to determine thedesired antenna for transmission; and switching, by the controller, theRF switch to the first position responsive to a determination that thefirst antenna is the desired antenna for transmission, wherein thecontroller adjusts the RF switch to select the second position accordingto the first reflection measurements and a stored efficiency valuecorresponding to a location on a two-dimensional tuning grid.
 10. Themethod of claim 9, wherein the controller adjusts the RF switch toselect between the first and second positions during a time period inwhich a modem of the communication device enables an antenna switch. 11.The method of claim 9, wherein the controller adjusts the RF switch toselect the second position according to the first reflectionmeasurements and a stored free space reference value.
 12. The method ofclaim 9, wherein the adjusting of the RF switch to select the secondposition is based on a distance measured from free space designated onthe two-dimensional tuning grid.
 13. A communication device, comprising:a modem; a transceiver; an antenna system coupled with the transceiver,wherein the antenna system includes a first antenna and a secondantenna, wherein one of the first or second antennas is operating as aprimary antenna and another of the first or second antennas is operatingas a diversity antenna; an RF switch connected with the antenna system,wherein the RF switch has a first position in which the first antenna isthe primary antenna and the second antenna is the diversity antenna, andwherein the RF switch has a second position in which the second antennais the primary antenna and the first antenna is the diversity antenna;and a controller coupled with the RF switch, wherein the controllerreceives first reflection measurements associated with the antennasystem, wherein the controller adjusts the RF switch to select betweenthe first and second positions according to the first reflectionmeasurements and during a time period in which the modem enables anantenna switch, wherein the controller adjusts the RF switch to selectbetween the first and second positions according to the first reflectionmeasurements and a stored efficiency value corresponding to a locationon a tuning grid.
 14. The communication device of claim 13, furthercomprising a matching network coupled with the transceiver and theantenna system, wherein the matching network comprises a tunablereactive element, and wherein the controller adjusts the tunablereactive element according to the first reflection measurements toprovide impedance tuning.
 15. The communication device of claim 14,wherein the tunable reactive element comprises a first tunable reactiveelement coupled with the first antenna and a second tunable reactiveelement coupled with the second antenna, and wherein tuning values forthe first and second tunable reactive elements are selected according toimproving impedance tuning of a receive-only function of one of thefirst or second antennas and compromising impedance tuning betweentransmit and receive functions of ffthell another of the first or secondantennas.
 16. The communication device of claim 13, wherein thecontroller adjusts the RF switch to select between the first and secondpositions according to the first reflection measurements and one of astored free space reference value or a distance measured from free spacedesignated on a stored tuning grid.
 17. The communication device ofclaim 13, wherein the controller receives sensed parameters associatedwith the communication device, wherein the adjusting of the RF switch toselect between the first and second positions is according to the firstreflection measurements and the sensed parameters, and wherein thesensed parameters include at least one of proximity data, firstcapacitive data associated with the antenna system, or second capacitivedata associated with a touch screen.